1. learn to use [itex]\LaTeX[/itex] here.
2. looks like homework.
3. except for [itex]x[0][/itex], if all other [itex]x[n][/itex] is zero, what would [itex]y[n][/itex] look like? (that might give you a hint about what [itex]h[n][/itex] might be.)
4. integrate [itex]h[n][/itex] to get the step response.